1. Field of the Invention
This invention relates to an information reading apparatus for reading information recorded to an information sheet and an image forming apparatus having the information reading apparatus attached to a main body thereof for forming information read by the information reading apparatus onto a sheet.
2. Description of Related Art
A conventional information reading apparatus is attached to a main body of an image forming apparatus, such as a copier, a printer, a facsimile machine, or a multi-function machine including these image forming apparatuses, in which the information reading apparatus conveys an information sheet, e.g., an original document, to an information reading portion thereof and reads letters, pictures or the like (hereinafter referred to as “images”) formed on the original document.
The so-called stationary reading method, which reads an image by moving an information reading portion upon an original document stationarily positioned on a platen, and the so-called feed reading method, which reads an image by positioning an information reading portion and moving an original document on a platen, are reading methods (scanning methods) for reading an image on an original document.
Information reading apparatuses in recent years employ the feed reading method for improving productivity (increasing the readable amount of original documents per time) and for reducing apparatus size; furthermore, the information reading apparatuses also employ a method of reading a front side and back side of an original document in a single conveyance by having two information reading portions therein for improving productivity.
In a conventional information reading apparatus 180 shown in FIG. 13 to FIG. 16, a reading targeted original document placed on an original document feeding tray 111, starting from an uppermost placed original document, is conveyed in-between a separation conveying roller 103 and a separation pad 104 by an original document feeding roller 101. When plural overlapped original documents are conveyed, the separation conveying roller 103 and the separation pad 104 separate the original documents to a single original document and convey the separated single original document.
The separated single original document is skew corrected by a resist roller pair 121 arranged downstream, is then passed through a roller pair 122, 124 and a roller pair 123, 124 as shown in FIG. 14, and is then guided to a first contact sensor 127. The first contact sensor 127 reads image information recorded on one side (front side, upper side when placed on the original document feeding tray 11) of an original document D.
The original document D is then passed through a roller pair 125, 124 as shown in FIG. 15, and is guided to a second contact sensor 128. The second contact sensor 128 reads image information recorded on the other side of the original document D (back side, bottom side when placed on the original document feeding tray 111). Finally, the original document, as shown in FIG. 16, is directly guided to an original document delivery roller pair 116, and is delivered upon an original document delivery tray 119.
When an image is formed only on one side of an original document mounted on the original document feeding tray (when a single-side mode is selected), the information reading apparatus 180 shown in FIG. 13 allows image information to be read by the first contact sensor 127 while having the second contact sensor 128 in a non-active state. Accordingly, the original document has image information thereof read by the first contact sensor 127 and is then directly delivered to the original document delivery tray 119 by the original document delivery roller pair 116.
Since the conventional information reading apparatus only has one original document conveying path, an original document having image information formed on both sides thereof cannot be read when one of the contact sensors is disabled. Even reading of an original document having image information formed on one side becomes impossible when, for example, the first contact sensor 127 is disabled.
Furthermore, the contact sensor opens and closes with respect to the platen and creates a shock or the like whenever an original document is placed on the platen, and thereby causes damage to one of the contact sensors (makes reading impossible) and prevents image information from being read precisely. Image information is also prevented from being read precisely even when the image information is formed on a single side of the original document.
It is an object of this invention to provide an information reading apparatus capable of reading image information formed on both sides of an original document even when one of the contact sensors thereof is unable to perform reading, and an image forming apparatus having the information reading apparatus attached thereto for forming a high quality image upon a sheet.